The present invention relates to the calibration of test devices for testing devices under test (DUT).
For testing electronic devices as DUTs using a network analyzer as a test device, in particular for testing integrated electronic circuits providing digital electrical output signals, a test or stimulus signal is fed to an input of the device under test, and a response signal of the device under test is evaluated by an automatic test equipment, for example by comparison with expected data.
A corresponding test device or network analyzer is an instrument used to analyze the properties of electrical networks, especially those properties associated with the reflection and transmission of electrical signals known as scattering parameters (S-parameters). To ensure accuracy of a network analyzer, a network analyzer has to be calibrated before use.
U.S. Pat. No. 4,921,347 discloses that in a method and an apparatus for calibrating absolute and relative measurements of modulation and/or demodulation transfer characteristics of electro-optical and opto-electrical devices during setup of a lightwave component measurement system for characterizing performance of fiber optic systems and associated components, an initial calibration reference is established based on the known characteristics of a lightwave source and lightwave receiver included in the lightwave component measurement system. A measurement is then performed on the calibration reference (the lightwave source or the lightwave receiver), and error correction data are produced and stored in a lightwave component analyzer included in the lightwave component measurement system. The modulation (or demodulation) transfer characteristics are preferably given in terms of the responsivity magnitude and phase versus modulation frequency. A device under test (DUT) then is measured when it replaces its calibrated counterpart in the measurement setup. The lightwave component analyzer uses the error correction data when the E/O or O/E characteristics of the DUT are measured.
U.S. Pat. No. 5,175,492 discloses another calibration system for calibrating a network analyzer.
However, conventional calibration systems for network analyzers may lack sufficient functionality.